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THE CHEMISTRY

COOKING AND CLEANING

A MANUAL 'for HOUSEKEEPERS

ELLEN IL RICHARDS

Instructor in Chemistry, Woman's Laboratory,

Massachusetts Institute of Technology,

Boston

BOSTON
ESTES & LAURIAT

301 — 305 WASHINGTON ST

1542)

PREFACE.

TN this age of applied science, every opportunity
of benefiting the household should be seized
upon.

The family is the heart of the country's life, and every
philanthropist or social scientist must begin at that
point. Whatever, then, will enlighten the mind, and
lighten the burden of care, of every housekeeper will be
a boon.

At the present time, when the electric light and
the gas stove are familiar topics, there is, after all, no
branch of science which might be of more benefit to
the community, if it were properly understood, than
Chemistry — the Chemistry of Common Life. John-
ston's excellent book with that title deserves a wider
circulation, and a more careful studjr.

viii PREFACE.

But there is a space yet unoccupied for an elemen-
tary work which shall give to non-scientific readers
some practical information as to the chemical com-
position of articles of daily use, and as to their action
in the various operations in which they are employed.

The public are the more ready for the application
of this knowledge since Chemistry is taught in nearly
all High Schools, and every child has a dim idea of
what some part of it means. To gather up into a
definite and practical form these indistinct notions is
the aim of this little book.

There is, lingering in the air, a great awe of chem-
istry and chemical terms, an inheritance from the age
of alchemy. Every chemist can recall instances by
the score in which manufacturers have asked for
recipes for making some substitute for a well-known
article, and have expected the most absurd results to
follow the simple mixing of two substances. Chemicals
are supposed by the multitude to be all-powerful, and
great advantage is taken of this credulity by unscrupulous
manufacturers.

The number of patent compounds thrown upon the
market under fanciful and taking names is a witness

PREFACE. Ix

to the apathy of housekeepers. It is time that they
should bestir themselves for their own protection. A
little knowledge of the right kind cannot hurt them,
and it will surely bring a large return in comfort and
economy.

These mysterious chemicals are not so many or so
complicated in structure but that a little patient study
will enable any one to understand the laws of their
action, as far as they are concerned in the common
operations of the household.

No attempt is here made to cover the whole ground
of chemical science, but only to explain such of its
principles as are involved in the raising of bread, and
in a few other common processes.

CONTENTS.

Chap. PAr.K.

I. Introduction, , , r

II. Starch. Sugat, and Fat, as Food. . i6

III. Nitrogenous Food and the Chemistry

OF Nutrition, . . . '*. . -37

PART II.

I. The CntLMisTRY of Cleaning, . . -55

II. Chemic.\ls for Household Use, . . .80

CHAPTER I.

INTRODUCTION.

T^T'E recognize substances, as we know people,
by their characters (properties) and by
their appearance. Sugar we call sweet ; if any-
'thing is sour/ we call it acid. Sugar and salt
dissolve in water. Carbonic acid gas will extin-
guish the flame of a candle. These are proper-
ties of the several substances. A teaspoonful of
sugar heated over a fire turns black, swells up
to a large bulk, emits a gas which, burns with a
smoky flame, and finally there is left a black,
crumbly mass, which seems like what it is, fine
charcoal. There is nothing which we consider
su;;ar left, no sweetness, none of the properties
vvhich we know under the name of sugar. There

2 THE CHEMISTRT OF

is a change, a loss of identity. This change is
called a chemical one.

Add a solution of an acid to a solution of
an alkali, and observe that the acid substance and
the alkaline substance are no longer in existence
as such. There is, instead, a neutral saline sub-
stance dissolved in water. The new substance
has not the properties of either of the others.
The acid and the alkali have both lost their
identity. A chemical change, then, involves a loss
of identity.

" We must be very careful not to transfer our
ideas of composition, drawn chiefly from the mix-
tures we use in common life, directly to chem-
istry. In these mixtures the product partakes, to
a _^reater or less degree, of the character of its
constituents, which can be recognized, -essentially
unchanged, in the new material. In all instances
of true chemical union and decomposition, the
qualities of the substances concerned in the pro-
cess entirely disappear, and wholly different sub-
stances with new qualities appear in their place."*

* "The New Chemistry." — Josiah P. Cooke. /. 99.

COOKING AND CLEANING. 3

All the substances about which we know any-
thing are composed of a few elementary bodies.
The grain of wheat, the flesh of animals, the
dangerous poison, all are capable of being sep-
arated into the simple substances of which they
are composed. The chemical element is that
substance out of which nothing essentially differ-
ent* has ever yet been obtained. Pure gold is
an element, a simple substance, from which nothing
can be taken different from itself. A gold coin
contains a little copper or silver, or both, and is
not pure gold ; it is a mixture of two or more
elementary substances. The oxygen in the air is
an element, a single thing. Water is a compound
of two elements, oxygen and hydrogen, which are
gases when they exist as simple substances.

There are about seventy of these elementary
substances known to the chemist ; about ten or
twelve of them enter into the compounds which
we use in the kitchen. The others are found only
in the chemical laboratory or in the physician's
medicine case, and a few are so rare as to be

* "Treatise on Chemistry." — Roscoe & Schorlemmer. p. 51.

4 THE CHEMISTRY OF

considered curiosities. Most of these elements
unite with each other, and, in the compounds thus
formed, other elements may exchange places with
those already there, so that a few elementary
bodies, by the variety of combination, make up
the objects of daily use.

To understand something of the nature of these
chemical substances and their common forms is
a necessity for every housekeeper who would not
be cheated of her money and her time.

It is important for every one to remember that
laws govern all chemical changes; for one is often
asked to believe that some chemical sleight of hand
can make one pound of washing-soda worth as
much as two, and that some special preparation
of flour will give a third more bread than any
other.

As has been said, we recognize substances by
their properties, and the chemical elements have
two essential characteristics vvhich must be con-
sidered at the outset of our discussion.

It is assumed that they are composed of homo-
geneous, particles, the so-called atoms, the smallest

COOKING AND CLEANING. 5

masses of matter which enter into chemical com-
bination. The particles have a definite weight,
constant for each substance. This weight is known
in chemistry as the atomic weight.

Hydrogen being the lightest substance yet known,
its atomic weight is taken as the unit.

TABLE I.

NAME.

SYMBOL.

ATOMIC WEIGHT.

Hydrogen

Sodium (Natrium)

Calcium

Oxygen

Carbon

The atom of oxygen weighs 16, and the atom of
calcium 40 times as much as the atom of hydrogen.
The letters or symbols in chemical formulae rep-
resent this definite weight, so that while the word
oxygen means only that collection of properties
to which we give the name, the letter O in a
formula indicates also 16 times the weight of H,
which is taken as i.

These symbols give a definiteness to the chemical

6 THE CHEMISTRr OF

terms which words merely cannot convey, and
therefore they are a great aid to the right com-
prehension of the laws of combination. In a table
at the end of the book will be found the atomic
weight of all the elements referred to in the text.

The atoms of each element have also their own
value in uniting and exchanging places with the
others.

The unit of value is an arbitrary standard. Some-
thing else might have been taken than the unit
chosen, but the relative value of all the elements
as compared wiih each other is constant.

At the outposts of the Hudson's Bay Territory
all trade is on a system of barter or exchange, and
a basis of value is necessary. The skin of a beaver
is agreed upon as the unit from which to count
all values. For example : a red fox skin is worth
two beaver skins, a silver fox skin is worth
four beaver skins. All of the hunter's stock is
valued in tliis way, and also articles to be purchased
are valued by the same standard, a knife is pur-
chased for four beaver skins, a gun is worth three
silver fox or twelve beaver skins. Chemists have

COOKING AND CLEANING. 7

agreed upon a unit of value in exchange, and the
unit thus agreed upon is the atomic weight of
hydrogen above referred to ; that is, the smallest
relative weight of hydrogen known to enter into
combination with other elements. It is, in a sense,
an arbitrary choice, but having once accepted it
as the unit, we can count all other values, in union
or in exchange, from its value.

TABLE

//.

NUMBER

OF ATOMS OF

HYDROGEN

WHICH

THE ATOM OF

THE SUBSTANCE WILI, RE-

NAME. SYMBOL.

PLACE ;

IN COMPOUNDS.

Sodium (Natrium) Na

Calcium Ca

Oxygen 0

Carbon C

For the convenience of the reader, this exchange-
able value will be indicated by the numbers over
the letters in the formulae given in this book,
although the practice is not universal.

The chemist has constructed a sign language,
based upon these two properties of the elements,
which aids the mind in grasping the idea of

8 THE CHEMISTRT OF

chemical changes. The symbols are, as it were,
the chemist's alphabet.

The non-scientific reader is apt to look upon
the acquisition of this sign language as the
school-boy regards the study of Chinese — as the
work of a lifetime. While this view might not
be so very far from the truth, if one were to
attempt to remember all the symbols of the com-
plicated compounds which are possible in the
union and interchange of the seventy or more
elements, yet the properties and combinations of
the dozen of them which make up the common
substances of daily use are not beyond the reach
of the busy housewife, and can be comprehended
in a few hours of thoughtful reading. " To mas-
ter the symbolical language of chemistry, so as to
fully understand what it expresses, is a great step
towards mastering the science."*

Hydrogen seems to be the connecting link be-
tween the other elements, which may, for our
present purpose, be divided into two classes, as
shown in

* " 'I'he New Chemistry." /. X49>

COOKING AND CLEANING,

TABLE III.

Some elements

which can

Some elements which imite

be substituted for

with H,

and with

H, and for each other in

Class I., as

well

as with

chemical compounds.

each

other.

BXCHANGE

EXCHANGE

VALtm.

VALUE.

Sodium

Na 1

Chlorine

CI I

Potassium

K I

Oxygen

O 2

Calcium

II
Ca 2

Hydrogen

Carbon

I
H 1

C 4

I I

H unites with CI, and forms HCl, or muriatic
I I

acid. K exchanges places witli H, and the new

III II

compound is KCl. Hj unites with O, and forms

I II 1 I
H2O, or water. Kg exchanges places with H2,

I II IV

and the new compound is K2O. C unites with

II IV II

O2 and forms CO2, carbon dioxide, or carbonic

IV 11 I II

acid gas. CO2 unites with H2O, and becom.es

I IV II I

H2CO3, or carbonic acid in solution. Nag ex-

I
changes places with H2, and the new compound

10 THE CHEMISTRY OF

I IV II
is Na2C03, or commercial soda ash, the compound

with which the laundress is familiar, under the

name of washing crystal.

The letters mean always the smallest relative

quantity known to combine with anything else,

and when the elements combine in more than

one proportion, we indicate it by writing two

I I

times or three times the units. Thus H, or 2H

I
means twice the unit value of H.

Some of the compounds formed by the union
of the elements given in the Tables are very
familiar substances.

I ir

H2O Water.

I X 2, 16 Two parts by weight of hydrogen.
Sixteen parts by weight of oxygen.

I O will unite with 2 H.

II II

Ca O Quick-lime.

40, 16 Forty parts by weight of calcium.

Sixteen parts by weight of oxygen.

I Ca will exchange places with 2 H.
IV II
C O2 Carbonic acid gas.

12, 16 X 2 Twelve parts by weight of carbon.

Thirty-two parts by weight of oxygen.

COOKING AND CLEANING. i ll

■ The exchanges and interchanges of the ele-
ments according to these two laws of value and
weight are chemical reactions, and the expres-
sion of them is called a chemical equation. A
certain modicum of chemical arithmetic is essen-
tial to the right understanding of these reactions.

" In the laboratory we never mix our materials
at random, but always weigh out the exact pro-
jjortions . . . for, if the least excess
of one or the other substance over the propor-
tions indicated is taken, that excess will be wasted.
It will "not enter into the chemical change."*

In the economy of nature nothing is lost. The
wood and coal burned in our stoves do not
vanisli into thin air, without adding to its weight.
Twelve lbs. of coal (not counting the ash), in
burning, take 32 lbs. of oxygen, and there are
formed 44 lbs. of carbonic acid gas.

In all chemical equations there is just as much
in weight represented on the one side of the
sign of equahty (=) as on the other.

* "The New Chemistry."' /. 151.

12 THE CHEMISTRT OF

For instance, in the equation

II I I II II 1 II

HCl + NaHO = NaCl + H^O

Muriatic Caustic Sodium Water.

Acid. Soda. Chloride or

Salt

36.5 + 40 = 58.5 + 18
76.5 = 76.5

The sum of the weights ot the two substances
taken is equal to the sum of the weights of the
two new substances formed as the result of the
reaction.

The present science of chemistry may be said
to date from the discovery of the law of definite
proportions, which gave a firm basis for all cal-
culations. If we wish to obtain 44 lbs. of car-
bonic acid gas (carbon dioxide), we can tell
just how much pure charcoal must be taken, by
writing out the reaction thus :

IV I IV 11
C -f O, = C O.

The atomic weight of Carbon is 12, X i = 12
The atomic weight of Oxygen is 16, X 2 = 32

44
Therefore 12 lbs. of charcoal must be burned
in order to obtnin 44 lbs. of carbonic acid gas.

COOKING AND CLEANING. 13

This law of definite proportion by weight can-
not be too strongly emphasized. It is the inva-
riable rule of chemical action, and it will be
referred to again and again in discussing the
chemical changes occurring in cooking and in
digestion.

When more than two elements enter into com-
bination, it is common for two or more to band
together, and in this case the group h<is an
exchange value of its own, which is not the sum
of the values of the separate elements, but which
is constant, and dependent upon these values in
a way which it is not necessary to explain here.

These partnerships will be included in brackets
II II I

as (SO^) (CO3) (NO3), not that these letters

represent actual compounds existing by themselves,

I II IV II II I
as do H2O, CO2, CaCi2, but that the group en-
closed in the brackets passes from one compound
into another as if it were only one element, and
the numbers over the bracketed letters will indi-
cate the exchange value of the partnership, not
of the elements separately. A few illustrations
will serve to make this clearer.

14 THE GHEMISTRT OF

TABLE IV.

Mineral Acids and Compounds :

I I I I I TI I 11

HCl H(N03) H,(S04) H^CCOs)

Muriatic. Nitric. Sulphuric. Carbonic

I I I I II II II II

NaCl KCNOa) Ca(S04) C*(CO,)

Salt. Saltpetre. Plaster of Marble.

Paris.

Reactions and Equations :

I II II II 11 II I II

H,(S04) + Ca(CO0 = Ca(S04) + H^CCOj)

1 II I I I II II

H..(S04) + 2(NaCI) = Na.,(S04) + 2(HC1)

I II II I I II II

H2(S04) + NaCr =NaH(S04)+ HCl

It will be seen that the groups do not sep-
arate, but that they combine with the single
elements by the same law as that which governs
the combinations of the simple substances.

It is also to be observed that where two atoms

of hydrogen can be replaced in a compound, as

I II
in IIo(S04), either one or both can be exchanged

for an atom of equal replacing value, and the

two compounds thus formed will differ in their

properties. This will be shown later on, in the

case of cream of tartar.

OF COOKING AND CLEANING. 15

For a full and clear exposition of the principles
of the science, the reader is referred to " The
New Chemistry," by J. P, Cooke.

CHAPTER II.

STARCH, SUGAR, AND FAT, AS FOOD.

"\^7"HEREVER there is life, there is chemical
change, and as a rule a certain degree of
heat is necessary, in order that chemical change
may occur. Vegetation does not begin in the colder
climates until the air becomes warmed by the
heat of spring. When the cold blasts of winter
come upon the land, vegetation ceases. If plant
life is to be sustained during a northern winter,
artificial warmth must be supplied. This is done
by keeping up a furnace or stove heat. In
chemical terms, carbon from coal, wood, or gas
is caused to unite with the oxygen of the air to
form carbonic acid gas, and by this union of two
elements, heat is produced :

COOKING AND CLEANING. 17

IV II IV II

C + O2 = C O,.
In wood and gas there is another compound
which is utilized :

IV I II IV II I II

CH4 + O4 = COi + 2 H2O.

These two chemical reactions express the changes
which cause the production of artificial heat used
for domestic purposes.

As many animals live in temperatures in which
plants would die, it is evident that they must
have some source of heat in themselves. This
is found in the union of the oxygen of the air
breathed, with the carbonaceous matter eaten as
food, and the formation of carbonic acid and

IV II I II

water (COo and H2O), just as in the case of the
combustion of the wood in the grate. Only, in-
stead of this union taking place in one spot, and
so rapidly as to be accompanied by light, as in
the case of the grate fire, it takes place in each
drop of the fluid circulating in the body, and so
slowly and continuously as not to be noticed-
Nevertheless the chemical reaction seems to be
identical.

18 THE CHEMISTRY OF

The first condition of animal life to be studied
is, then, that portion of the food which supplies
the heat necessary for the other chemical changes
to take place. The class of foods which will be
here considered as those for the production of
animal heat, includes carbon compounds, chiefly
composed of carbon, hydrogen, and oxygen.

These carbonaceous bodies need abundance of
oxygen for their slow combustion or oxidation,
and hence the diet of the animal must include
fresh air, — a point too often overlooked. It does
not make a bright fire to pile on the coal
without opening the draught.

A certain quantity of heat is produced by other
causes than this combustion of carbon compounds,
which will be considered later, but the best
authorities seem to now agree that the chief heat-
producing foods used by the human race include
starch, sugar, and fot.

Starch is the first in importance, both from its
wide distribution and its extensive use. Starch is
found in all plants in greater or less abundance.
It is laid up in large quantities in the seeds of

COOKING AND CLEANING. 19

many species. Rice is nearly pure starch, wheat
and the other cereals contain sixty to seventy
per cent of it. Some tubers contain it, as pota-
toes, although in less quantity, ten to twenty per
cent. It is formed from the carbonic acid gas
and water contained in the air, by means of the
living plant-cell and the sun's rays, and it is
the*cnd of the plant life, the stored energy of the
summer, prepared for the early life of the young
plant another year.

Common sugar, cane-sugar, is found in fruits
and the juices of some plants. It is directly or
indirectly a product of plant life. The chemical
transformations of starch and sugar have" been
very carefully and scientifically studied, with refer-
ence to brewing and wine-making.

Several of the operations concerned necessitate
great precision in respect to temperature and
length of time, and these operations bear a close
analogy to the process of bread-making by means
of yeast. The general principles on which the
conversion of starch into sugar, and sugar into
[ikohol, are conducted, will therefore be stated as

20 THE CHEMISTRr OF

preliminary to a discussion of starch and sugar as
food.

There are two distinct means known to the
chemist, by which this change can be produced.
One is by the use of acid and heat, which
changes the starch into sugar, but can go no
farther. The other is by the use of a class of
substances called ferments, some of which #iave
the power of changing the starch into sugar, and
others of changing the sugar into alcohol and
carbonic acid gas. These substances are in great
variety, and the. germs of some of them are always
present in the air.

A substance is formed in sprouting grain which
is called diastase, or starch converter, which first
changes the starch into sugar or glucose, under
the influence of warmth, as is seen in the pre-
paration of malt for brewing. The principal
chemical change is expressed by the following
re-action :

IV I II I II IV I II

Cb H,o ©6 -f Hj O -I- ferment = Ce H,a Ob
Starch. Water. Sugar (glucose).

The sugar formed from starch is one of the

COOKING AND CLEANING. 21

class of sugars commonly called glucose. These

sugars differ in some of their properties from

ordinary cane sugar, but cane sugar is easily
changed into glucose :

IV I ' 11 I II IV I II

C,,Hs2 0n + H, O + ferment = 2 C„ H,, Oa
Cane Sugar. Water. Glucose.

So, whether we start with starch or cane-sugar,
glucose is produced by one kind of fermentation,
and this glucose is then converted by yeast into
alcohol and carbonic acid. In beer, the alcohol
is the product desired, but in bread-making the
chief object of the fermentation is to produce
carbonic acid to puff up the bread, the alcohol
escapes in the baking.

IV I II
2 Ca Ho O
Alcohol.
1 IV II

Dextrose. 2 C Oj

IV I II

L/6 -1112 Oe =

Carbonic Acid Gas.

The alcohol, if burned, would give carbonic
acid gas and water.

IV I II II IV II I II

2 Ca He O + 12 O = 4 C Oa -t- 6 Ha O

Alcohol. Oxygen. Carbonic Water.

Acid Gas.

It will be seen that the total number of atoms

22 THE CHEMISTRY OF

of carbon remains constant. There are six in the
starch, and 2+4=6 in the carbonic acid gas
at the end, and but two atoms of hydrogen have
been added, while 13 atoms of oxygen have been
required; hence, 16 lbs. of starch will yield
26 lbs. of carbonic acid gas and 10.8 lbs.
of water, more than double the weight of the
starch. These products of decomposition are
given back to the air in the same fonii in
which those substances existed from which the
starch was originally formed.

The same cycle of chemical changes goes on
in the human body when starchy . substances are
taken as food. Such food, moistened and warmed
in the mouth, becomes mixed with air, by reason
of the property of the sahva to form froth, also
it is impregnated with ptyalin, a substance which
can change starch into sugar, as can the diastase
of the malt. The mass then passes into the stomach,
and the change once begun, goes on. As soon as
the sugar is formed, it is absorbed into the circula-
tory system and is in some manner oxidized,
changed into carbonic acid gas and water.

COOKING AND CLEANING. 23

No starch is used in the human system as such ;
it must undergo this transformation into sugar be-
fore it can be absorbed. Whatever of it passes out
of the stomach unchanged, meets a very active
converter in the pancreatic juice. If grains of
starch escape these two agents, they leave the
system in the same form as that in which they
entered it.

The cooking of pure starch as rice, farina, etc.,
requires httle explanation. The starch grains are
prepared by the plant to keep during a season of
cold or drought, and are very close and compact ;
they need to be swollen and distended by moisture
in order that the chemical change may take place
readily, as it is a law that the finer the particles,
the sooner a given change takes place. For in-
stance, i)owdered alum will dissolve in water much
sooner than a crystal of alum, or marble-dust in
acid sooner than a piece of marble. Starch grains
may increase in bulk twenty-five times in process
of hydration.

The cooking of the potato and other starch-
containing vegetables, is likewise a mechanical

24 THE CHEMISTRY OF

process very necessary as a preparation for the
chemical action of digestion ; for raw starch has
been shown to require a far longer time and
more digestive power than cooked starch. Little
change can take place in the mouth when the
starch is not heated and swollen, and in case the
pancreatic secretion is disturbed the starch may
not become converted at all.

The most important of all the articles of diet
which can be classed under the head of starch
foods is bread. AVheat bread is not solely starch
but it contains a larger percentage of starch than
of anything else, and it must be discussed under
this topic.

Bread of some kind has been used by man-
kind from the first dawn of civilization. During
tlie earlier stages it consisted chiefly of powdered
meal and water, baked in the sun, or on hot
stones. This kind of bread had the 'same char-
acteristics as the modern sea-biscuit, crabkers and
hoe-cake, as fur as digestibility was concerned.
It had great density, it was difficult to masticate,
and the starch in it presented but little more

COOKING AND CLEANING. 25

surface to the digestive fluids than that in the
hard compact grain, the seed of the plant.

Experience must have taught the semi-civilized
man that a light porous loaf was more digestible
than a dense one. Probably some dough was
accidentally left over, until fermentation had set in
and the possibility of porous bread was thus sug-
gested.

The ideal loaf, light, spongy, with a crispness
and sweet pleasant taste, is not only aesthetically,
but chemically, considered the best form in which
starch can be presented to the digestive organs.
The porous condition is desired in order that as
large a surface as possible shall be presented to
the action of the chemical converter, tlie ptyalin
of the saliva. There is also a better aeration in
the process of mastication.

Very early in tiie history of the human race,
leavened bread seems to have been used-. This
was made by allowing flour and water to stand
in a warm place until decomposition had well set
in. A portion of this dough was used to start
fermentation in fresh portions of flour and water

26 THE CHEMISTRY OF

to be made into bread. This kind of bread had
to be made with great care, lest lactic acid and
other bodies, unpleasant to the taste, should be
formed.

Because of this disagreeable taste, and because
of the possibility that the dough might reach
the stage of putrid fermentation, chemists and
physicians sought for some other means of ren-
dering the bread light and porous. The search
began almost as soon as chemistry was worthy
the name of science, and one of the early
patents bears the date 1837. A good deal of
time and thought has been devoted to tlie per-
fecting of unfermented bread ; but since the
process of beer making has been universally
introduced, yeast has been readily obtained, and
is an effectual means of giving to the bread a
pleasant taste. Since tlie chemistry of the yeast
fermentation has been better understood, a change
of opinion has come about, and nearly all scien-
tific and medical men now recommend fermented
bread.

The chemical reactions concerned in bread raising

COOKING AND CLEANING. 27

are identical with those in beer making. To the
flour and warmed water is added yeast, a sub-
stance capable of causing the alcoholic fermenta-
tion. The yeast begins to act upon the starch
at once, .especially if the dough is of a semifluid
consistency, but no change is evident to the eye
for some hours, as the formation of sugar gives
rise to no other products :

IV I II I II IV I II

C„Hu,05 + H, O = C„H.sO.

Starch. Water. Sugar.

But as soon as the sugar is decomposed into
alcohol and carbonic acid gas, the latter product
makes itself known by the bubbles which appear
and the consequent swelling of the whole mass.

, IV I II

( 2C, H„0

ly ^ U ) Alcohol.

CbHioOs =

IV II

Sugar. J 2C O.,

^ Carbonic Acid Gas.

It is the carbonic acid gas (carbon dioxide)
which causes the sponge-like condition of the loaf
by reason of the peculiar tenacity of the gluten,
one of the constituents of wheat. It is a well-
known fact that no other kind of grain will make

28 THE CHEMIST R r OF

as light bread as wheat. It is the right propor-
tion of gluten (a nitrogenous substance to be
considered later), which enables the light loaf to
be made of wheat flour.

The production of carbonic acid gas is the end
of the chemical process, the rest is purely me-
chanical. The kneading is for the purpose of
rendering the dough elastic by a spreading out
and thorough incorporation of the already fer-
mented mass with the fresh flour.

Another reason for kneading is, that the bubbles
of gas may be broken up into as small portions
as possible, in order that there may be no large
holes, but only very fine ones, evenly distributed
through the loaf, when it is baked.

The temperature at which the dough should be
maintained during the chemical process, is the
most important point. A lesson can be learned
from the distillers of spirit. The best temperature
for the first stage of the alcoholic femientation
is 70° to 75° F., the maximum is 82° to 90°.
Above 90°, the production of acetic acid is liable
to occur. ^

COOKING AND CLEANimT."^ 29

IV I II 11 IV I II I II

C, Hr. O + O, = C, H4 O^ + Hs O.

Alcohol. Acetic Acid.

The more dense the dough, the more yeast is
needed. After the dough is stiffened by the fresh
flour and is nearly ready for the. oven, the tem-
perature may be raised to 160° or 165° F., the
temperature of the beer mash. A quick change
then occurs which is so soon stopped by the heat
of the oven, that no time is allowed for souring.

In the use of leaven, the lactic fermentation
is liable to take place, because sour dough often
contains a ferment different from ordinary yeast,
and this produces a different set of reactions.

The temperature should be carefully regulated, if
light and sweet bread is desired. The baking 6f
the loaf has for its object to kill the fermejit,
to heat the starch sufficiently to render it easily
soluble, to expand the carbonic acid gas and
drive off the alcohol, and' to "form . a crust which
shall have a pleasant flavor. The oven must be
hot enough to raise the temperature of the inside
of the loaf to 212° F. The most favorable tem-
perature for baking is 400° to 550** F.

30 THE CHEMISTRY OF

The brown coloration of the crust, which gives
a peculiar flavor to the loaf, is probably caused
by decomposition due to the high heat. Some
dextrine may be formed. One hundred pounds of
flour are said to make from 126 to 150 pounds
of bread. This increa.se of weight is due to the
incorporation of water, very possibly by a chem-
ical union, as the water does not dry out of the
loaf as it does out of a sponge.

The bread seems moist when first taken from
the oven, and dry after standing some hours, but
the weight will be found nearly the same. It is
this probable chemical change which makes the
difference, to delicate stomachs, between fresh bread
and stale. A thick loaf is best eaten after it is
twenty-four hours old, although it is said to be
" done," when ten hours have passed. Thin biscuits
do not show the same ill effects when eaten hot.
The bread must be \vell baked in any case, in order
that the process of fermentation may be stopped.

The expansion of water or ice into 1700 times
its volume of steam is sometimes taken advantage
of in making snow-bread, water gems, etc. It

COOKING AND CLEANING. 31

plays a part in the lightening of pastry and of
crackers.

Air, at 70°, expands to about three times its
volume at the temperature of a hot oven, 'SO that
if air is entangled in a mass of dough, it gives
a certain lightness when the whole is baked. This
is the cause of the sponginess of cakes made with
eggs. The viscous albumen catches the air and
holds it, even when it is expanded, unless the
oven is too hot, when the sudden expansion^ is
liable to burst the bubbles and the cake falls. /

As has been said, the production of the porous
condition, by means of carbonic acid, generated in
some other way than by the decomposition of
starch, was the study of practical chemists for
some years. Among the first methods proposed,
was one undoubtedly the best theoretically, but
very difficult to put in practice, viz., the liberation
of carbonic acid gas from bi-carbonate of sodium,
by means of muriatic acid.

I I IV II II

Na H C O3 4- H CI =
Soda. Hydrochloric

Acid.

II I II IV
= Na CI 4- Ha O • -f- C Oi,

32 THE CHEMISTRY OF

The difficulty lies in the fact that this libera-
tion of gas is instantaneous on the contact of the
acid with the soda, and only a skilled hand can
mix the bread and place it in the oven without
the loss of much of the gas. Tartaric acid, the
acid phosphates, sour milk (lactic acid), vinegar
(acetic acid), alum, all of which have been used,
are open to the same objection. Cream of tartar
is the only acid substance commonly used which
does not liberate the gas by simple contact in
the cold. It unites with soda only when heated,
because it is very slightly soluble in cold water.
For the even distribution of the gas by thorough
mixing, cream of tartar would seem to be the
best. The chemical reaction is shown in the table
on page 49 But as,- beside gas, there are other
products which remain behind in the bread, in
the case of all the so-called baking powders,
the healthfulness of these residues must be con-
sidered.

Common salt, the residue from the first-men-
tioned reaction, is the safest, and perhaps the
residues from acid phosphate are next in order.

COOKING AND CLEANING. 33

The tartrate, lactate, and acetate of sodium are
not known to be especially hurtful. As the im-
portant constituent of Seidlitz powders is Rpchelle
salt, the same compound as that resulting from the
use of cream of tartar and soda, it is not likely
to be very deleterious, taken in the small quantities
in which even habitual "soda-biscuit" eaters take
it.

The various products formed by the chemical
decomposition of alum and soda are possibly the
most injurious, as the sulphates are supposed to
be the leasts readily absorbed salts. Taking into
consideration the advantage given by the insolubility
of cream of tartar in cold water, and the com-
paratively little danger from its derivative, Rochelle
salt, it would seem to be, on the whole, the best
substance to add to the soda in order to liberate
the gas ; but the proportions must be chemically
exact, according to the reaction given. At least,
there must be no alkali left, for a reason which
will be given under the head of hindrances to
digestion.

Hence, baking powders prepared by weight

34 THE CHEMISTRY OF

and carefully mixed, are a great improvement on
the teaspoonful measured by guess. The reactions
of the various baking powders with the proportions
of each will be given on page 49.

Another group of substances which, by their slow
combustion or oxidation in the animal body, yield
carbonic acid gas and water, and furnish heat to
the system, comprises the animal fats : as, for
instance — suet, lard and butter ; and the vegetable
oils, as ohve oil, the oily matter in corn, oats, etc.

These fatty materials all have a similar compo-
sition, containing when pure only carbon, hydrogen,
and oxygen. They differ from starch and sugar
in the proportion of oxygen to the carbon and
hydrogen, there being very little oxygen relatively
in the fatty group, hence more must be taken from
the air for their combustion.

CinHadOi Ce H|o O5

Stearic Acid in Suet. Starch.

One pound of starch requires one and two-tenths
pounds of oxygen, while one pound of suet requires
about three pounds of oxygen for perfect combus-
tion. At the same time, a greater quantity of heat

COOKING AND CLEANING. 35

can be obtained from the fats, pound for pound,
than from starch or sugar ; hence, people in Arctic
regions require fat,

A most noticeable difference between the starch
group and the fat group, is that the latter is stored
up in the system against a time of need. This is
the more easily done, since the fats do not seem
to undergo any essential change in order that they
may be absorbed. They pass the mouth and stomach
without any chemical change, and only when they
encounter the bile and the other intestinal juices,
is there any question as to what happens.

With these fluids, the brie especially, the fats
form emulsions in which the globules are finely
divided and rendered capable of passing through
the membranes into the circulatory system. The
change, if any, is not one destructive of the proper-
ties of the fatty matters. The globules are carried
along by the blood, and deposited wherever needed,
to fill up the spaces in the muscular tissue, and
to serve as a reserve supply of fuel.

There seems to be good reason for believing
that the animal does derive some fat from the

36 THi» CHEMISTRY OF COOKING, ETC,

other constituents of its food, but it is not an
important question in the diet of mankind, for
even the rice eaters use butter or oil with their
food.

It must not be inferred from what has been said
that the oxidation of starch and fat is the only
source of heat in the animal body. A certain
quantity is undoubtedly derived from the chemical
changes of the other portions of food, but the
chemistry of these changes is not yet fully under-
stood.

CHAPTER III.

NITROGENOUS FOOD AND THE CHEMISTRY OF NUTRITION.-

TN the previous chapter, the food necessary for
the existence of the adult animal was con-
sidered ; but animals do more than exist, they
move and exert force, in mechanical terms they
do work; also the young animal grows.

For growth and work, something else is needed
beside starch and fat. The muscles are the in-
struments of motion and they must grow and be
nourished, in order that they may have power.
The nourishment is carried to them by the blood
corpuscles. We find in these, as well as in mus-
cular tissue, an element which we have not here-
tofore considered, nitrogen. We find it also in the
products of their decomposition, hence we reason

38 THE CHEMISTRT OF

that if the wear and tear of the muscles causes
the liberation of nitrogenous compounds, which
pass out of the system as such, this loss myst
be supplied by the use of some kind of food
which contains nitrogen. Starch and fat do not ;
therefore they cannot furnish it to the blood.

The typical food of this class is albumen, white
of egg ; hence the terms albuminous and albuminoid
are often used as descriptive of the group. The
other common articles of diet containing nitrogen
are the casein of milk, the musculine of animal
flesh, the gluten of wheat, and the legumen of
peas and beans. The proportion of the element
in each is shown in the table on page 53.

The chemical changes which these bodies un-
dergo are not well understood. The nitrogenous
food is finely comminuted in the mouth, because,
as before stated, chemical action is rapid in pro-
portion to the fineness of division ; but it is in
the stomach that the first chemical change occurs.

The agents of this change are the pepsin and
the acid of the gastric juice ; the two together \
render the nitrogenous substance soluble and dia-

COOKING AND CLEANING. 39

lysable, capable of passing through the membranes.
Neither seems able to do this alone, and it
■does not seem to matter what acid is present so
long as it is acid and just acid enough ; but if the
acid is neutralized, action ceases ; hence the danger
of soda biscuit with too much soda.

The chemical changes which go on after the
albumen is taken into the system are not known.
A decomposition of some sort takes place, and the
nitrogen passes out of the system in urea, being
separated by the' kidneys, as carbonic acid gas is
by the lungs.

The effect of cooking upon nitrogenous food
should be such as will render the substance more
soluble, because in this case digestibility means
solubility. Therefore white of egg (albumen) and
curd of milk (casein), when hardened by heat,
must not be swallowed in lumps.

In the case of flesh, the cooking should soften
and loosen the connecting tissue, so that the little
bundles of fibre, which contain the nutriment, may
fall apart easily when brought in contact with the
teeth. Any process which toughens and hardens

40 THE CHEMISTRY OF

the meat should be avoided. The cooking of
beans and all leguminous vegetables should soften
and loosen the compact grains. Hard water should
be avoided, as an insoluble lime or magnesia com-
pound of legumen is formed.

We have now considered the three classes of
food under one or more of which all staple articles
of diet may be placed — the starch food, the fats and
the nitrogenous material. Some general principles of
diet, indicated by science, remain to be discussed.

One of the most obvious questions is : Which is
best, — starch or fat, beans and peas, or flesh?
As to starch or fat, the question has been answered
by experience, and science has only tried to explain
the reason. The colder the climate the more fat
the people eat. The tropical nations live chiefly
on starch foods, as rice. From the statements on
page 50, it will be seen that this is right ; fat yields
more heat than rice. Therefore the inference is
plain that in the cold of winter fat is appropriate
food, while in the heat of summer rice or some
other starch food should be substituted.

No such evident rule can be seen in the case

COOKING AND CLEANING. 41

of the albuminous foods. At most, the class can
be divided into three groups. The first includes
the material of vegetable origin, as peas, lentils,
and the gluten of wheat. The second comprises
the white of egg and the curd of milk, material of
animal origin. The third takes in all the animal
flesh used by mankind as food.

Considering the question from a purely chemical
stancHtJoint, without regarding the moral or social
aspects of the case, two points stand out clearly :
I St. If the stored-up vegetable matter has required
tJie force derived from the sun to prepare it, the
tearing apart, and giving back to the air and earth,
the elements of which it was built up, will yield
so much force to whatever tears it down ; but a
certain amount of energy must be used up in
this destruction. 2nd. If the animal, having accom-
plished this decomposition of the vegetable, and
appropriated the material, is killed, and the pre-
pared nitrogenous food in the form of muscle is
eaten by man, then no force is necessary to render
the food assimilable ; it is only to be dissolved
in order that it may enter into the circulation.

42 THE CHEMISTRY OF

The force-producing power is not lost ; it is
only transferred to another animal body. Hence
the ox or the sheep can do a part of man's
work for him in preparing the vegetable food for
vise, and man may thus accomplish more than he
otherwise could. There is, however, another side
to this question. Nearly all, if not all, j^oung
animals live on food of animal origin. The young
of the human race live on milk, but it has been
found by experience that milk is not the best
food for the adult to live upon to the exclusion
of all else. It is not conducjve to quickness of
thought or general bodily activity.

This fact, with many others, leads us to the
conclusion that mankind needs some vegetable
food. Two other facts sustain this inference. The
digestive organs of the herbivorous animals form
fifteen to twenty per cent, of the whole weight
of the body. Those of the carnivorous animals
form five to six per cent., those of the human
race about eight per cent. The length of the
canal through which the food passes bears about
the same relation in the three classes. A mixed

COOKING AND CLEANING. 4^

diet seems to be indicated as desirable by every
test which has been applied, but the propoEtions
in which the vegetable and animal food are to be
mingled, as well as the relative quantities of car-
bonaceous and nitrogenous material which will give
the best efficiency to the human machine are not
so easily determined.

Dietaries, based upon experience and chemical
analysis, have been prepared for soldiers' rations,
and for use in prisons. Many cook-books and
most works ,on physiology give lists of quantities.

One who has studied the question for years
says : " Not only the age and occupation, but
also the individuality of the person play an im-
portant part in the regulation of diet, and decide
not only the quantity but also the kind of the
food, and the form in which it is to be taken . .
For the proper assimilation of the nourishment and
its complete effect in the organism, the food must
be agreeable ; it must relish . . A supply of
needful nourishment is not enough. Man requires
yet more. He must find his food pleasing to the
taste . . The boiling and roasting of food

44 THE CHEMISTRY OF

materials are operations wliich we find only among
civilized people, and they have been developed
with the advance of civilization. The whole art
of cooking amounts to this : So to prepare the
food that it will best answer its end." *

The nutrition of the animal body, that is, the
assimilation of the food taken, is dependent upon
absorption. Absorption is dependent upon pre-
vious chemical ]:)rocesses. These processes are
contingent upon the secretions, the saliva, the
gastric juice, etc. \ and it is a well-known fact
that the flow of these liquids is, to a great ex-
tent, under the control of the nerves. Whatever
excites the nerves pleasantly, causes an abundant
secretion of the chemical agents of food change.
In this fact lies the secret of modern cooking, the
judicious use of condiments.

Pettenkofer (Konig, page 21) says of condi-
ments : " I may compare them to the right use
of lubricants for an engine, which indeed cannot
replace the steam power, but may help it to a

* Die menschlichen Nahrungs-und Genussmittel, von Dr. J. Ronig.
Berlin, 1880. /. 100.

COOKING AND CLEANING. 45

much easier and more regular action, and besides,
prevent quite naturally the wearing out of the
machine. In order to be able to do this, one
condition is absolutely essential : the lubricant must
not attack the machine, it must be harmless "

Cooking has thus become an art worthy the
attention of intelligent and learned women. The
laws of chemical action are founded upon the law
of ' definite proportions, and whatever is added
more than enough, is in the way. The head of
every household should study the condition of her
family, and tempt them with dainty dishes if that
is what they need. If the ashes have accumulated
in the grate, she will call a servant to shake them
out so that the fire may burn. If she sees that
the ashes of the food previously taken are clog-
ging the vital energy of her child, she will send
him out into the air, with oxygen and exercise to
make him happy, but she will not give him more
food.

Nature seems to have made provision for the
excess of heat, resulting from the oxidation of
too much starch or fat, by the ready means of

46 THE CHEMISTRY OF

evaporation of water from the surface, this loss of
water being suppHed by drinking in a fresh sup-
ply, which goes, without change, into the circu-
lation. The greater the heat, the greater the
evaporatioft ; hence the importance of water as an
article of diet must not be overlooked. For an
active person, the supply has been estimated at
three quarts per day. Water is the heat regulator
of the animal body.

While dangerous disease seldom seems to result
from eating an excess of starch or fat, because
the portion not wanted is rejected as so much
sand, many of the most complicated disorders
do result from an excess of nitrogen diet.

The readiness with which such substances undergo
putrefaction^ and the many noxious products to
which such changes give rise, should lead us to
be more careful ns to the quantity of food.

A growing person needs about one part of
nitrogenous food to four of starch and fat ; a grown
person, one part nitrogenous food to five or six
of starch and fat. A fair average ration per day
is perhaps :

COOKING AND CLEANING. 47

Bread i lb. lo oz.

Fat I to 2 oz.

Rice (cooked) i lb.

Flesh i lb.

All processes of cooking and the use of all con-
diments which hinder digestion should be avoided.
Woody fibre or cellulose, as bran, irritates the
digestive canal, and causes it to empty itself of
the food before the chemical change is complete.
An excess of sugar sometimes decomposes with
the formation of acids which have the same effect.

Tannin, tobacco, salt in excess, and alcohol, all
harden the albuminous part of the food, and by
this means hinder solution.

Certain substances, as alcohol and coffee, lessen
the amount of food needed for the time being.

The fats all decompose at about 300° F., into
various bodies, some of them exceedingly acrid
and irritating to the mucous membrane of the nose
and throat, and which must also prove offensive
to the lining of the stomach. This is probably the
reason why many people cannot bear food fried
in ^

48 THE CHEMISTRY OF

In counting the cost of the several articles of
diet, not only the price per pound, but the digesti-
bility must be taken into account.

It has been found by experiment that of the
total starch in rice less than one per cent, is
rejected, while in potatoes nearly eight per cent, is
not used. (See table, page 52).

The cost of a diet which derives all the nitrogen
from the animal kingdom has been estimated in
Germany as 9.2 marks per day; while an entire
vegetable diet, giving the same chemical con-
struction, is given at 1.95 marks per day. This
is a very evident reason why the working people
of all lands (except America) Hve on vegetable
food almost entirely.

COOKING AND CLEANING. 49

t.li o

%lo

+ ^ +

-^K ^ + +

6 o I d

^•a

_ ... Ox I. -2 6 ^P S R Jl-

^ (3'^ + + + +

t . "^- 1% o 6

. -O EK =K j!j "E +

I + ^ -S + ^

« 0;soSt^ ^

-g^-ll ^ i ^"i ;? d

^ + ■ + ^ ->< E

-O . - ^ - O

U ^ « -O . ^n . U! ^

THE CHEMISTRY OF

2 <n ^£
- 3 So •

3 *

00 t^ lo

.«

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*t^

S§

sgs

^ bis

<Z^

<r>

'*•

2> \0 \0 lo rt- t-^ ,

ON fO 0 "I t>. VO •<

N to ■»!• d <> to fO

to t>. t^ *» J>i

fO t>. 00

.2 E

£ -s

- S bo

^ ^ 5 '- •^'"

M >< 3

o o s

bo ^ t!

cao O

fcifepQOwumuu

COOKING AND CLEANING.

■4-

^fe

1 3 S*^"

|g«S

■f

t>. in 00 >o ^ 00 Q

■<*-■* fO t>. M ON VO

•H 1-1 f/J

»0

■<t-

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>-<'-'i-iOvOrOcsvO'-'

\0 \0 00
to M *;•

ro to fO fj

CO to t»

■^ ■^ CO to ro fo 00
M M ro t- 00 00 t-»

S ^

x:
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fj*

fr.

52 THE CHEMISTRY OF

Digestibility of some articles of food shown
by the per cent, of the several constituents re-
jected :

Nitrogen.

Fat.

Starch Matter.

Maize

15-5

17-5

3-2

Rice

20.4

7-1

•9

Potatoes

32.2

3-7

7.6

Macaroni

17.1

5-7

1.2

Yellow Beets

39-0

6.4

18.2

White Bread

18.7

Roast Meat

2.5

21. 1

Eggs

2.9

5-0

Milk

7.0

7-1

Butter

"•3

2.7

Bacon

12. 1

17.4

It has been estimated (Moleschott) that a work-
ing man needs daily 130 grms,* of nitrogenous
food and 448 grms. of non-nitrogenous food, starch,
fat, etc.

The following table shows the weights of the
different kinds of food which must be eaten in
order that the required quantity may be obtained;

* s8 gnns. = i ounce nearly.

COOKING AND CLEANING.

For

130 grms.

Nitrogenous
Substances.

448 grms.

Non-nitrogenous

Substances.

Cheese

338

Rice

572

Lentils

491

Maize

625

Peas

582

White Bread

631

Beans " Acke

Lentils

806

bohnen "

590

Peas

819

Ox Flesh

614

Beans "Acke

Eggs

968

bohnen "

823

White Bread

1.444

Eggs

902

Corn

1,642

Rye Bread

930

Rice

2,562

Cheese

2,011

Rje Bread

2.875

Potatoes

2,039

Potatoes

lO.CXX)

Ox Flesh

2,261

Daily Rations in grms.

Albuminous
[(nitrogenous) Starch Mineral

Food. Fat. Food. Salts. Water.

Soldier's Ration

(ordinary)

119

48s

Soldier's Ration

(very rich)

116

209

400

Working Men

148

526

30 2858

(Mean of estimates by 12 different authorities.)

54 THE CHEMISTRY OF COOKING^ ETC.

The daily need of a woman is counted as
three-fourths or four-fifths that of a man.

Elementary (

COMPOSl

[TION IN

< of C.

Vegetable Albumen 53.1

7.2

20.5

17.6

T.6

Egg " 534

7.0

22.4

15-7

1,6

Flesh (Fowl) 53.18

7.03

.48

15-75

1-S6

Casein (Curd of Milk) 53.5

7-05

.88

15-77

Of 100 parts of food (solid and liquid) taken,
is discharged :

By the Intestines 6.7 per cent.

" " Kidneys 49.3 «' "

" *' Skin and Lungs 42.6 " "

PART II.

CHAPTER I.

THE CHEMISTRY OF CLEANING.

"jVTEXT to the materials for food, those used for
the very necessary operations of cleaning are
perhaps of greatest interest to the housekeeper.

This chapter will discuss the properties of the
chemical substances which are suited to aid in
performing the work of cleansing to the best
advantage,
.y/ First in importance among these chemical ma-
terials are soap and its substitutes.

" Whether the extended use of soap be preceded
or succeeded by an improvement in any com-
munity— whether it be the precursor or the result
of a higher degree of refinement amongst the
ss

56 THE CHEMISTRT OF

nations of the earth — the remark of Licbig must
be acknowledged to be true, that the quantity of
soap consumed by a nation would be no inaccurate
measure whereby to estimate its wealth and civiliza-
tion. Of two countries with an equal amount of
population, the wealthiest and most highly civilized
will consume the greatest weight of soap. This
consumption does not subserve sensual gratification,
nor depend upon fashion, but upon the feeling of
the beauty, comfort and welfare attendant upon
cleanliness ; and a regard to this feeling is coin-
cident with wealth and civilization." *

It is surely a problem of the greatest interest to '
every housekeeper, how to keep her household
and its belongings in a state of cleanliness that '
shall be a state of perfect health ; for a large
portion of disease is a direct result of uncleanly
ways.. [The toleration of impure air in close rooms
is one of the most common, as well as one of the
most easily remedied of these uncleanly ways.]

This state of cleanness must also be attained
at the least cost in money, time and labor. Such

• Muspratt's Chemistry as applied to Arts and Mattu/aciures.

COOKING AND CLEANING. 57

a question ought to stir the business capacity of
every woman in charge of a house. As we have
said, soap and its substitutes justly claim, first
of all, our attention.

Many primitive peoples find a substitute for soap
in the roots, bark or fruit of certain plants. Nearly
every country is known to produce such vegetable
soaps, the quality whicli they possess of forming
an eniulsio-n with oily substances being due to a
peculiar vegetable substance, known as Saponin.
Many of these saponaceous barks and fruits are
now used with good results — the "soap bark"
of the druggist being one of the best substances
for dressing over black dress goods, whether of
silk or woollen.

The fruit of the Soapberry tree — Papindus
Saponaria — a native of the West Indies, is said
to be capable of cleansing as much linen as sixty
times its weight of soap.

Wood ashes were probably used as cleansing
material long before soap was made, as well as
long after its general use. Their properties and
value will be considered later.

58 THE CHEMISTRY OF

Soaps for laundry use are chiefly composed of
alkaline bases, combined with fatty acids. Their
action is "gently but efficiently to dispose the
greasy dirt of the clothes and oily exudations of /
the skin to miscibility with, and solubility in wash
water." *

We may state it in this way. All kinds of
cleansing, whether it be of our skins, our clothes,
our painted wood -work, our windows or our dishes,
consist of two distinct operations : first, the solu-
tion or emulsion of the oily matter which causes
the dust and dirt to adhere ; second, the mechan-
ical removal of the dust and dirt, which, in most
cases, is effected by water. Sometimes, as in the
case of silver and paint, the cleansing agent is
fine sand or chalk.

It will readily be seen that the first operation —
the removal of the oily matter — is of prime im-
portance in the laundry. In order clearly to
understand the question of the best means to
secure this removal, we must first- consider the

* Chemistry applied to the Manufacture of Soaps and Candles.
Morfit.

COOKING AND CLEANING. 59

properties of the grease and oily matters, and next,
what agents will dissolve them or form an emulsion
with them.

Oily matters in general are soluble in certain 1
substances, as salt is soluble in water, and can be /
recovered in their original form from such solutions
by simple evaporation. Some of them readily
combine with alkalies to form the kind of com-
pound which we call soap. Others in contact with
the alkalies form emulsions, so-called, in which the
fatty globules are suspended, forming an opaque
liquid. These emulsions are capable of being in-
definitely diluted with clear water, and by this means
the fatty globules are all carried away. The opacity
of soap-suds is due to the fact that it contains
particles in suspension, the nature of which will be
presently shown.

Setting aside the vegetable saponin, we have
then two classes of agents which affect oily mat-
ters,— the one class by simple solution, as turpen-
tine, alcohol, ether, benzine, etc. ; the other class
by a direft union, or by the formation of an
emulsion. Agents of the latter class are substances

60 THE CHEMISTRY OF

known in chemistry as the alkali metals, and in
order to justify the somewhat extended discussion
of these alkali metals, we must remind our readers
that the value of all soaps as detergents depends
upon the alkali chiefly. To the distinguished
French chemist, Chevreul, is due our knowledge
of the action of soaps.

"The neutral salts formed by the alkalies and the
fat acids are decomposed by the water, whereby
insoluble double fat acid salts, — stearates, palmi-
tates, oleates — are separated, while the alkali is
set free. By means of the free alkali the im-
purities clinging to the materials are removed."

Every woman must have noticed the peculiar
opaque appearance of soap-suds, even before any-
thing has been washed in it. This is due to the
suspension in the water of the particles of these
"insoluble double fat acid salts."

[Hot water will dissolve soaps without this de-
composition, but on cooling the separation takes
place.]

As each soap-maker claims that his product
contains something which renders it better than

COOKING AND CLEANING. 61

Other soaps, or different from them, and as the
chief stress in his recommendation rests on the
fatty matters used, " Oil soap is superior to resin
soap," and the hke, it behooves the housekeeper
to remember that, within certain Hmits of course,
the kind of fatty acid does not so much matter
to her (provided only that it is not putrid or
otherwise unfit for use) as the quantity and quality
of the alkali, and as she is often called upon to
believe that some new chemical has just been
discovered which makes a far more efficient soap
than the world has ^ever before seen, it may be
instructive for her to follow our discussions of the
alkali metals and their compounds.

The chemical group of " alkali metals " com-
prises six substances — Ammonium, Caesium, Lithium,
Potassium, Rubidium and Sodium. Two of the
six — Caesium and Rubidium — were discovered by
means of the spectroscope, not many years ago, in
the mineral waters of Diirckheim, and probably
the total amount for sale of all the salts of these
metals, could be carried in one's pocket. A third
alkali metal — Lithium — occurs in several minerals,

62 THE CHEMISTRY OF

and its salts are of frequent use in the laboratory,
but it is not sufficientl}^ abundant to be of com-
mercial importance.

As regards the three remaining alkali metals, the
1 1 II -.^

hydrate of Ammonium, (NH4) HO, is known as ''Vola- ^

I I II
tile Alkah," the hydrates of Potassium, KHO. and

I I II
Sodium, NaHO, as " Caustic Alkalies." With these

three alkahes and their compounds, and tiiese alone,
are we concerned in housekeeping. The volatile
alkali, Ammonia, has been recently prepared in quan-
tity and price such that every housekeeper may
l/ccome acquainted with its use. It does not often
occur in soaps, and its use is confined to the more
delicate cleansing operations, the bath, the washing
of woollens, and other cases where its property of
evaporating, without leaving any residue to attack the
fabric or to attract anything from the air, is invaluable.
This property affords a safeguard against the care-
lessness of the laundress in not sufficiently rinsing
the fabric, and this imperfect rinsing is at the bottom
of most of the trouble in washing woollens with
soap or caustic alkah. All flannels worn next the

COOKING AND CLEANING. 63

skin, all the woollens of an infant's wardrobe, should
be washed in water made soft and alkaline by
ammonia, or ammonium carbonate. An additional
advantiige will be found in the fact that the shrink-
age of woollens thus washed is very slight. The
ammonium compounds are somewhat more ex-
pensive than the caustic alkalies, but in the present
time, when an amnion iacal liquor is largely produced
as a secondary product in the manufacture of coal
gas, the cost is not excessive compared with the
benefit its use confers. For use . in the bath, and
for woollens, the ammoniacal gas liquor must have
passed through a process of purification, in order
to free it from some other products of the de-
structive distillation of coal, which is not healthful
or useful. This caution must be borne in mind,
as a crude article is sometimes sold for ^eaning
paint or carpets ; this is not fit for the uses we
have been specifying.

Ammonia water, bought of the best dealers in
chemicals and druggists' supplies, costs about 30
cents a pint, without the bottle.

A pint of this liquid possesses as much alkaline

64 THE CHEMISTRY OF

1 IV II I II

value as ten ounces of sal soda, Na2C03+ loHgO,

and has not the injurious properties of the latter,

even when used in excess. As the alkali is volatile,

and water nearly boiling will retain only about one

seventh as much of the ammonia gas as water at

the ordinary temperature of the air, it will be seen

that the directions on the various botdes of

" Magical " washing fluids which contain ammonia,

to pour the required quantity into hot water, with

the word " hot " especially emphasized, are at

variance with the known properties of this sub

stance. The fluid should be largely diluted with

cold water, and then added to the warm water.

never to water too hot to bear the hand in.

Ammonia is most excellent for cleaning glass
(but not for brass, as it dissolves copper, and
copper salts).

A teaspoonful of ammonin, added to a quart
of water, is the best possible agent for cleansing
hair brushes.

For use in travelling, the solid ammonium car-
bonate is preferable ; for use in hard water it is

COOKING AND CLEANING. G5

also better, as the lime is precipitated out by it as
by sal soda. It costs twenty-five or thirty cents
a pound, and one pound of it is of as much
alkaline v. due as two pounds of sal soda.

Some compounds of the two alkali metals, Potas-
sium and Sodium, are capable of saponifying fats
and forming the complex substances known as
soaps.

For the » compounds of . these alkalies, employed
in the manufacture of soap, we shall use the
popular terms "potash" and "soda," as less likely
tj cause confusijn in our readers' minds. Potash
makes soft soap ; soda makes hard soap. Potash
is derived from wood ashes, and in the days of
oi.r grandmothers soft soap was the universal
.detergent. Potash (often called Pearlash) was
cheap and abundant. The wood fires of every
household furnished a waste product ready for its
extraction. Soda ash was, at that time, obtained
from the ashes of sea-weed, and of course was
not common inland. Aerated Pearlash (Potassium
bicarbonate), under the name of saleratus, was used
for bread.

66 THE CHEMISTRr OF

The discovery by the French manufacturer,
Leblanc, of a process of making soda ash from
the cheap and abundant sodium chloride, or com-
mon salt, has quite reversed the conditions of the
use of the two alkalies. Potash is now some
eight cents a pound, soda ash is only three.

In 1834, Mr. James Muspratt, of Liverpool, first
carried out the Leblanc process on a large scale,
and he is said to have been compelled to give
away soda by the ton to the soap-boilers, before
he could convince them that it was better than
the ashes of kelp, which they were using on a
small scale. But the soap trade, as we now know
it, came into existence after the soap-makers real-
ized the value of the new process. Soda ash is
now the cheapest form of alkali, and housekeepers
will do well to remember this fact when they are
tempted to buy some new " ine," or "crystal."

In regard to the best form in which to use tlic
alkali for washing purposes, experience is the best
guide, — that is, experience reinforced by judgment ;
for the num.ber of soaps, and soap substitutes, in
the market is so great, and the names so little

COOKING AND CLEANING. 67

indicative of their value, that only some general
information can be given.

In the purchase of soap, it is safest to choose
the make of some well-known and long-established
firm, of which there are several who have a repu-
tation to lose if their product is not good ; and,
for an additional agent, stronger thart soap, it is
better to buy sal soda (sodium carbonate) and
use it knowingly, than to trust to the highly lauded
packages of the grocery. A pound of sal soda
contains from four to five times as much alkali as
a pound of hard soap, and therefore it should
be used with care.

Washing soda should never be used in the solid
form, but should be dissolved in a separate vessel,
and the solution used with judgment. The inju-
dicious use of the solid is probably the cause of
the disfavor with which it is so often regarded.
One of the most highly recommended of the scores
of " washing compounds " in the market, doubtless
owes its popularity to the following directions :
"Put the contents of the box into one quart of
boiling water, stir well, then add three quarts of

68 THE CHEMISTR T OF

cold water : this will make one gallon. For washing
clothes, allow two cupfuls of liquid to a large tub
of water."

As the package contains about a pound of
washing soda, this rule, which good housekeepers
have found so safe, means aJDOut two ounces to a
large tubful of water, and this in solution.

Ten pounds of washing soda can be purchased
of the grocer for the price of this one-pound
package, with its high-sounding name. Nearly all
the compounds in the market depend upon washing
soda for their efficiency. Usually they contain
nothing else. Sometimes soap is present and,
rarely, borax. In one or two, ammonia has been
found.

For hard water, a little sal soda is almost indis-
pensable. Borax is a very good cleansing agent
for many purposes. The sodium is in a milder
form than in washing soda. For delicate fabrics
and for many colored articles, it is the safest
substance to use.

On first thought, we may wonder why we need
to add these chemical agents to soap, when our

COOKING AND CLEANING. 69

grandmothers did without them ; but we must
remember that our grandmothers used soft soap
and wood ashes for all the cleansing operations
for which we now depend upon hard soap. It is
a recognized fact that soft soap is much more
caustic and hence more effective in removing
grease than hard soap. The reason for this lies
partly in the fact that the gelatinous character of
the soap allows a considerable proportion of free
lye to be mechanically held in the mass, and partly
because potash is a more powerful chemical agent
than soda.

Many prudent housewives still make soft soap
for their own use. Many more add to the effi-
ciency of the common soap by dissolving several
pounds of it in hot water, adding about one-third
as many pounds of sal soda, and allowing the
mass to cool into a white, soft curd.

A washing fluid, said to be of great value, is
prepared by the addition of freshly slaked lime to
a solution of sal soda. When the liquid has
become clear, alcohol is added to it, and it is
bottled for use.

70 THE CHEMISTRY OF

II I II
Slaked lime, CaH202, or caustic lime, and car-
I II
bonate of soda, Na2(C03), put together in solution,

II II
must inevitably result in carbonate of lime, Ca(C03),

I I IF

and caustic soda, 2NaH0, — a compound much
more dangerous to use in excess than sal soda.
The alcohol dilutes this caustic solution, and the
little gill cup used to measure the fluid for use,
insures safety. The mistress who considers herself
cautious will sanction the use of this "fluid," when
she will not allow sal soda to be used.

Turpentine has been sometimes recommended as
an addition to washing fluids, but its use may be
attended with danger, as, when applied in hot
water, to the bare arms of the laundress, it is
readily absorbed, and is liable to cause illness.

There is a compound of sodium of great value
for laundry and common use, which seems to take
the place of the old-time soft soap. This is sodium
silicate, water-glass, or soluble glass. It is manu-
factured for print works, and its common name is
"water-glass," that is, glass soluble in water, and
free from the lime or lead of the common w^indow-

COOKING AND CLEANING. 71

glass. Being made from clean materials, sand and
soda, or potash, it has no reminder of the dead
meat or bone-boiler's establishment, as soap some-
times has. The affinity of the alkali for the silica
is not strong, and yet it holds until some stronger
acid comes in contact with it. By virtue of this
property, it is said by the few housekeepers who
have hitherto had access to it, not to injure the
fabric, even if used in excess, and to give to
linen the clean, fresh appearance of new cloth.
It is hoped that an agent so valuable to the
housekeeper may soon be accessible to all.

The removal of spots from clothing is a subject
which has perplexed every woman.

The fabrics upon which we wish to operate are
nearly all colored, and the modern dye is such a
complex and unstable compound that disaster is
not uncommon.

.Chloroform, ether, alconol, benzine, turpentine,
all dissolve grease, but all are liable to show an
enlarged ring if not very carefully applied, and the
water in ethef and alcohol affects many colors.
Turpentine is useful for some coarser fabrics, but

72 THE C HE MI ST R V OF

for the most delicate silks and woollens benzine
or naphtha is the safest, not injuring the color, and,
if pure, completely volatile.

For grease on carpets or other articles, where
washing is out of the question, absorbents may
be used : such as powdered soapstone, magnesia,
buckwheat flour, etc.

These absorbents are also sometimes used to
remove spots other than those caused by grease.

Grass stains often baffle the best laundress. A
sure, if expensive, solvent for chlorophyl (the green
coloring matter of plants) is alcohol, if applied
while the stain is still fresh. Fruit stains are generally
removed by the well-known process of pouring
on boiling water. In some cases oxalic acid is
better.

Red iron rust is most readily soluble in muriatic
acid, and if one has a little knowledge of chemical
principles, this acid may be of great use in the
laundry. It is very readily washed out with clear
water, and it does not affect most fast colors. As
the iron compound formed is also soluble, it can
be taken away entirely. The efficacy of salt with

COOKING AND CLEANING. 73

lemon is probably due to the setting free of a small
amount of muriatic acid.

Black iron stains, as those from the inks made
with iron, may be best removed by oxalic acid,
although it has little effect on red iron stains.
The iron forms a colorless compound with the acid
but great care must be taken to remove all of it by
a thorough washing. The difificult solubility of oxahc
compounds makes this harder. It is., well to
wash the article with ammonia water finally, in
order to remove the last traces of acid. Oxalic
acid and ammonia are two of the" most useful
agents in the laundry. For further details, see
chapter II.

It may comfort some young housewife to know
that mildew is beyond the art of the chemist. It
seems to be a vegetable growth, which attacks
the cotton fibre, and in a measure destroys it, as
dry rot does a stick of timber. If it is superficial
only, successive washings and bleachings in the
sun will remove it. If deep seated, its removal is
hopeless ; as in other cases, prevention is the best
cure. Some cloth is very liable to mildew, and

74 THE CHEMISTRY OP

servants are often blamed for its appearance without
good cause.

We will now consider some of the preparations
for the mechanical removal of " matter in the wrong
place" — tarnish on silver, spots on paint, etc.

The matron of fifty years since, took care of her
silver herself, or superintended the cleanmg verv
closely, for the heirlooms were precious, or the
gifts of friends valuable. The silver was hardened
by a certain proportion of copper, and took a polish
of great brilliancy and permanence. The matron
of to-day, who has the same kind of silver, and
who takes the same care, is the exception. Plated
ware is found in nearly every household in our
villages. The silver deposited from the batter\'
is only a thin coating, and is of pure, soft metal —
very bright when new, but easily scratched, easily
tarnished, and never again capable of taking a beautiful
polish. The utensils, being of comparatively little
value, are left to the table-girl to clean, and of course
she uses the material which will save her labor.

In order to ascertain if there was any foundation
for the prevalent opinion that there was mercury

COOKING AND CLEANING. 75

or some equally dangerous chemical in the silver
powders commonly sold, we have purchased sam-
ples in Boston and vicinity, and in New York and
vicinity.

Thirty-eight different kinds have been found.

Of these,

25 were dry powder.
10 " partly liquid.
3 " soaps.

Of the twenty-five powders, fifteen were chalk
or precipitated calcium carbonate, with a little
coloring matter, usually rouge.

6 were diatomaceous earth.
2 " fine sand entirely.
2 " " '^ partly.

Mercury was found in none. No other injurious
chemical was found in any save the "electro-plating
battery in a bottle," which contained potassium
cyanide, KCN, a deadly poison ; but it was labelled
])oison, although the label also stated that "all salts
of silver are poison when taken internally. This
preparation does contain silver, and does deposit a
thin coating, but it is not a safe article.

76 THE CHEMISTRY OF

Of the nine polishes, partly liquid, five contained
alcohol and ammonia for the liquid portion ; four,
alcohol and sassafras extract. The solid portion,
in all cases, was chalk, with, in one case, the
addition of a little jeweller's rouge.

The caution to be observed in the use of these
preparations is in regard to the fineness of the
material. A few coarse grains will scratch the

II IVII

coating of soft silver. Precipitated chalk, CaCOa,

IVII

or well-washed diatomaceous earth, Si02, seem to
be of the most uniform fineness.

We may learn a lesson in this, as well as in
many other things, from the old-fashioned house-
wife. She bought a pound of whiting for twelve
cents, floated off the fine portion, or sifted it
through fine cloth, and obtained twelve ounces of
the same material, for three ounces of which the
modern matron pays twenty-five or fifty cents,
according to the name on the box.

Silver is liable to tarnish from many causes, some
of which can be avoided. Flannel is apt to con-
tain sulphur, and should not be used to wrap up

COOKING AND CLEANING. 77

silver articles. Clean, soft tissue paper first, then
a bag of Canton flannel, form a good covering.
Want of sufficient ventilation in a house shows
itself very quickly by the tarnish on the silver,
caused by foul air and coal gas.

Iron and steel oxidize in damp air, according
to the rule that the presence of water favors
chemical change. A little oily coating will exclude
the air and hence no oxidation can ensue.

The mechanical removal of spots on paint and
kitchen utensils is effected by scouring agents,

II IV II II IV II

such as chalk, CaCOa, whiting, impure CaCOj,
pumice and Bristol brick (silicates), fine sand

IV II

Si02, and preparations which owe their cleansing
properties to one of these solids.

A frequent source of annoyance is the bluing,
which seems to be indispensable to the city laun-
dress, who has not fresh grass, or the white snow
of the country on which to whiten her clothes.

Three substances are at present used for this
purpose. Indigo, from the plant Indigo tinctoria,
has been known from time immemorial. Soluble

78 THE CHEMISTRY OF '

Prussian blue, a chemical compound containing
iron, is a recent invention. Ultramarine, the third,
is a silicate, insoluble in water, giving a tint by
means of the very fine blue powder, which is im-
pacted in the cloth.

The indigo bags of olden time have been almost
entirely replaced by numerous " Soluble Blues,"
all of which are Prussian blue of greater or less
strength.

It must be borne in mind that this substance is
decomposed by the fixed alkalies, and if the clothes
are not rinsed free from soap-suds or washing
soda, mysterious iron-rust spots may appear on
the linen, caused by the decomposition of the
bluing. The general yellowish tint, which is so
often seen on linen, is probably due to this cause.

Of fifteen different kinds of bluing which were
examined, not one was anything but Prussian blue.
Here, as in so many other cases, the young house-
keeper who has had some training in a chemical
laboratory, has an advantage over one who has not,
in her idea of absolute cleanliness, and her con-
ception of the inexorable laws of chemical change.

(COOKING AND CLEANING. 79

A long chapter might be written on the subject
of economy in the case of the multitude of chemical
preparations so freely offered for sale. There is
so much for the young housewife to do that she
is tempted by every promise of making labor easier,
and is very ready to try anything that is
recommended.

She thinks that if her servants are provided with
all the modern appliances for doing work quickly
and well, it is their fault if they do not ac-
complish it. She forgets that the past generation
of women, who succeeded in keeping their familico
healthy and happy, brought brains to the work ;i
they knew, too, the properties of the substances i
they used, because they prepared them at home.

When American girls will learn to apply Chem-
istry and Physics to every-day life, we may hope
for a speedy solution of the servant-girl ques-
tion.

CHAPTER II.

CHEMICALS FOR HOUSEHOLD USE.

I . Adds.

nPHERE are three acids which should be found
in every laundry cupboard: acetic acid,

IV 1 II II

C2H4O2 ; muriatic or hydrochloric acid, H CI; and

IV I II

oxalic acid, C2H_04.

Vinegar can be used in many cases instead of
acetic acid ; but vinegar contains coloring matters
which stain delicate fabrics, and it is better to
use the purified acid, especially as the so-called
vinegar may contain sulphuric acid.

If soda has been spilled on black silk an ap-
plication of acetic acid will usually restore the
color.
to

THE CHEMISTRY OF COOKING, ETC. 81

Many of the bright blue flannels and other
fabrics found at the present time in our markets
owe their brilliant shades to an acid compound of
a coal-tar color, and as soon as they are washed
in soap or ammonia, the alkali neutralizes the
acid, and the color becomes pale and faded in
appearance. If acetic acid or vinegar is added to
the second rinsing water, the bright color is in all
such cases restored. This fact was discovered by
accident, and is well worth remembering. Of
course, not all shades of blue are made with this
compound, and hence not all faded blues can be
thus restored. It is well to test a bit of the
cloth before washing the whole garment.

A weak acid like acetic acid is safe to use on
many fabrics which would be injured by a strong
acid.

Muriatic or hydrochloric acid is useful in a
multitude of ways. By means of it, the writer
once restored, in a few minutes, a delicate blue
cambric dress, which had been quite ruined by nu-
merous large stains of red iron rust. The cloth was
laid over a large bowl half filled with hot water,

and the spots thus steamed were touched with a
drop of the acid, and as soon as the iron was
dissolved, the cloth was plunged into the water to
prevent injury to the cotton fibres. All the spots
were thus dissolved ofif; the garment was then
quickly rinsed in several waters, and finally in water
containing a little ammonia, which neutralized any
trace of acid still remaining. This process is by
far the best for removing red iron stains from
white cloth.

Porcelain or china, stained with iron, can be
■ cleaned with muriatic acid. For the porcelain or
enamelled water-closet basin it is especially useful,
but the acid must be removed by rinsing with
water followed by a little alkali to save the iron
pipes below.

The acid must not be used on marble, as it
dissolves it with great rapidity, and the polish is lost.

The property which muriatic acid, in common
with the so-called stronger acids, possesses — that of
liberating carbonic acid gas with brisk effervescence
from its compounds, renders this acid valuable for
the detection of carbonates.

COOKING AND CLEANING, 83

For instance, if the label of a washing powder
claims it to be something new, and requires that
it be vised without soda, as soda injures the clothes,
it can be tested as follows : Put half a teaspoonful
of the powder into a tumbler, add a little water,
then a few drops of muriatic acid. A brisk effer-
vescence will prove it to be a carbonate, and if
tl.e edge of the tumbler is held near the colorless
flame of an alcohol lamp, the characteristic yellow
color of sodium will complete the proof. If the
acid is added drop by drop until no more effer-
vescence occurs, and there remains a greasy scum
on the surface of the liquid in the tumbler, the
compound contains soap as well as sal soda, for
the acid unites with the alkali of the soap and
sets free the grease.

If some very costly silver polishing powder is
offered as superior to all other powders, a drop
or two of muriatic acid will decide whether or not

II IV II

it is chalk or whiting (CaCOs) by the efferves-
cence or liberation of the carbonic acid gas.

Oxalic acid is purchased in white crystals,
and for use a saturated solution is made j as one

S4 THE CHEMlSTRr OF

part of it dissolves only in several parts of water, it
is well to keep an excess of the crystals in the bottle.
It is somewhat poisonous, and should not be left
in the solid form within reach of careless people.
A small bottle of liguid can, however, be kept
with other laundry articles.

This acid is the only efficient means which is
known to the writer, for removing the shoe-
leather stains from white stockings. It will take
out most fruit stains on napkins and from the
fingers ; for the latter purpose tartaric acid will
also serve.

Oxalic acid is invaluable to the housekeeper
as a means of removing black iron stains, such as
those caused by the iron inks.

It is a more powerful acid than acetic acid,
and must be carefully removed from cloth by
rinsing with water and finally by ammonia.

Oxalic acid is very efficient as an agent for
cleaning brass, and seems even safer to use than
acetic, as the compound of the latter with copper
salts is one of the most dangerous of the copper
compounds.

COOKING AND CLEANING. 85

IV n
Sulphurous acid gas (SO2) is obtained by burn-
ing sulphur, and is the well-known agent for
bleaching. It will often remove spots which noth-
ing else will touch. The cloth or other substance
should be moistened and held over a bit of burning
julphur ; as the agent is an acid, the same pre-
cautions must be observed as in the case of the
other acids, as to the removal of the Corrosive
substance.

2. Alkalies.

The uses of ammonia water and ammonium carbon-
ate, have been considered in the text ; a precaution
to be taken is, chat the bottles should not be kept
with other bottles containing liquids for internal use,
as distressing accidents have occurred from swallow-
ing ammonia.

Caustic soda or potash is better for greasy tins
than soap; a swab should be used to apply it,
however, as it is corrosive to the hands. Silicate
of soda may also be used for this purpose.

Some alkali should be always at hand. The
alkali compounds, sodium carbonate (sal soda)

8G THE CHEMISTRr OF

I IV TI I II IT IV II

NagCOs + H 10 HjO and calcium carbonate CaCOg,

are of daily use as has been already explained in

the previous chapter.

BOOKS FOR REFERENCE.

For Teachers :

"History of Chemical Theory."

A. Wurtz.
Translated and edited by Henry Watts.

" Elementary Manual of Chemistry."

Eliot and Storer.

"Physiology and Hygiene." (Chapter on Digestion.)

Huxley and Toumans.

"Treatise on Chemistry."

Roscoe and Sckorlemmer.

For General Readers :

" Elements of Chemistry.'*

l^ Roy C. Cooley,

COOKING AND CLEANING. 87

"The Birth of Chemistry."

Rodiuell.

" Chemistry of Common Life."

Johnston and Church {neiv edition),

"The New Chemistry."

5^. P. Cooke.

"Lessons on Elementary Chemistry."

Henry E. Roscoe.

" Fermentation."

• Schlitzenberger.

" Vortrage uber die Entwickelungsgeschichte der Chemie
in den letzten Hundert Jahren."

Dr. A. Ladenburg.

Table of some common elements with their atomic
weights and symbols.

NAME. SYMBOL.

Hydrogen H

I
Chlorine CI

I
Sodium Na

I
Potassium K

I
Silver Ag

II
Oxygen O

II
Copper Cu

ATOMIC WRIGHT.

35-5

23-

39.1

108.

16.

63-4

THE CHEMISTRT OF COOKING, ETC.

NAME. SYMBOL.

Calcium Ca

Barium Ba

II
Lead Pb

III
Gold Au

III V

Nitrogen N or N

III V
Arsenic As or As

ATOMIC WEIGHT.
40.

137.
207.

Zinc Zn 65.3

III
Boron B

II.

197.

27.4

II IV

Iron Fe or Fe 56

II IV

Alurninum Al or Al

II IV

Tin Sn or Sn 118.

IV
Silicon Si 38.

IV
Carbon C

13.

14.

75.

INDEX.

Page.
Absorption of Food, ... 44

Aceiic Acid, 80

.Acids :

Acetic, ... ... 80

Hydro-cliloric or Muriatic, 80

Oxalic, vy^'o

Tartanc, 4q

Acid Phosi.ha;e, 40

Albumen, ...... 3S

Albiimimius Food, .... ^ 1

Alcoh'il, 2;-59-7i

Alkalies, ^1;

Caustic, 62

Volatil.' 62

Alum .^3-49

Ammonia, 61-63-64-S5

Ammonium Carbonate, . 63-''4-S5

Assunilatinn, 44

Atomic Weight ^

Baking Powders, ... . 32 49

Benzire, ST7^

Billing, 77

Mooks for Reference, ... 8'i

Borax fis

liread, 2\

F'ermented j'S

Reason for Kneading. . z-i
Temperature for Fe'n:eiit-

ing 2S

Temperature for Baking, 29

Snow Bread 30

Soda-Bread, .... 31-32-3?
Carbonic Acid Gas, . . . 27 31-40

Ca;sium 61

Chemical Change, .... 1-16

Element, 3

Equation 11

Reaction, ii

Chloroform, 71

Pagb.

Cleaning :

I'rass, 84

Brushes, 64

Gia^s, 64

Paint 64

Silv r, 74-75

Cookine ' . . 4^

OfStirch, 23

Of Niircgenous Food, . 39
Cdst of N tro;;unous and Vege-
table I >iet in Germany

compared 4S

Cream of T.irtar, 32-49

D uger :

Act tic -Vcid on Cupper, . 84

Ani'Tionia, S5

" B.I Icry in a Bo tie,"' . 7;

Hard water, ' 40

Soda I'j

'J'utpnline in Washing, . 70

Diastase, 20

Etlier, 59-7'

Fats. 34-35

Decompiisition of . . . 4/

Fruit Stains, 72

Glucose, 21

Gluten, 27

(Srass Stains, 72

( Ircase on Carpels, .... 72
Growth Nitrogenous Food re-
quired for, 37

Heat — Artificial, 16

Source of in Animals, . 17

Hea -proiiucirig Fond, ... 18

Ink Stairs, 73

Iron, niacin Stains of . . 73-82-84
Rust, ...... 72-78-81

Law of Definite Proportion l^

Weight, 13

INDEX.

Page.

Lime 70

Lithium 61

Magical Wasliing Fluids, . . 64

Milflew, 73

Milk 42

MutitticAcid 81

Ni'ropen, 37

Percepiageof in Food, . 50-53
Required in Growth and

Work 37

Oils 34-35

Ox:\l:c Acid 83

Pearl Asli, 65

Plate Powderf, 75

Pota>h, 65-85

Potassium, 61

Pttassium Cyanide, .... 75

Princ pies of I >iet, .... 40

Pripenies of Substances, . . i
Proportion of Nitrogenous

Food required, ... 46

Ptyaliii ill Saliva 22

Relation of Climate to Food, 40
Removal of Spots, . . . 71-72-85
Residues from Baking Pow-

d>rs, 32-33

Restoring Color, .... 80-81

Roclielle Salts, 49

Rubidium, 61

Rust of Iron, 72-81

Sal Soda, 65-67-85

Salt, 32-47

Saponin 57

Silver-Tarnish, 74

Snow-bread 30

Soap, S5-58

Bark t 57

Berry Tree, 57

Soda - . . 33-49-J'S

Soda Ash, 6b

Soda Bread 31-32-33

Sodium, 61

Carbonate, 67

Silicate 70

Soft Soap, 69

Page.

Soluble Glass 70

Stains 71-72-80-82-84

Starch, iS

Chemical Changes of . . 20

Cooking of 23

Sugar 20

Tabli^s:

1. Atomic Weights, . 5
II. ExLhangeab c Val-
ues, 7

III. Interchangeable

Values, ... 9

IV. Mineral Acids, . . 14
B.ik ng Powders ... 49
Composition of Some Ani-
mal Food, 50-54

Comrosiiicpu of Some

Veget.ble Food, . . 51-54
Comparative Digestibility

of Food 52

Daily Weight of Food

Required 53

Percentages of Waste, . 54

Tannin, 47

Temperature for Ferme.iting

Bread, 28

For Baking Bread. . . 29

Tests witli Muria.ic Acid, . 83

Tobacco, 47

Turpentine, _ 59-70-71

Trai:sfer of Force- Producing

Power, 42

Unit of Value, 6-7

Vinegar, 80

Volatile Alkali 67

Yeast, 27

Yellow Tint on Linen, ... 78

Washing Fluids 69-70

Washing Woollens 62-63

Water as the Htat-Regulator

of the Body, .... 46

Water Glass, 7°

Wood Ashes, 57-59

Work, Nitrogenous Food Re-

■ quired for 37

This ook is nilF o" ♦'- -

-f<?mped below

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